Q. Where can I buy building contract forms — cost estimate, weekly invoices, contract and subcontract agreements, etc.?

A.New England Business Systems (500 Main St., Groton, MA 01471; 508/448-6111) has stock forms, as well as some forms which match several of the popular computerized accounting systems. Home-Tech Systems (5161 River Rd., Bethesda, MD 20816; 800/638-8292) has a complete set of contractor forms. The R.S. Means Company (P.O. Box 800, Kingston, MA 02364-0800) also has forms available.